Our Voltimum Experts answer your questions on a daily basis in our Technical Expertise area. This Question of the Day, concerning entering Max Zs values on a 17th Edition Periodic Test Sheet, is answered by the NICEIC:
Or should I use the amended 80% values to allow for ambient temperature etc?
Answer: The values to be entered should be the tabulated values from BS 7671:2008. This is because the 80% figure only takes into consideration a typical temperature, usually 20oC. If the location was colder (or warmer), the 80% figure would need to be adjusted accordingly.
However, to comply, the loop impedance for the circuit under test is deemed acceptable if the measured value does not exceed 80% of the tabulated value. (Appendix 14 of BS 7671:2008 refers)
To see many more Q & A in Voltimum UK's Experts Area, please click on the link:
www.voltimum.co.uk/consult.php?universe=consult.index.questions